Introduction - TTI i-Prober 520 Manual De Instrucciones

Introduction

The Aim I-prober 520 is a unique device which is capable of observing and measuring current in PCB
tracks and other locations where conventional current probes cannot be used. It is a 'positional'
current probe which derives its measurement from the magnetic field at a defined position relative to
the current carrying conductor. This enables current observation and measurement from simply
placing the insulated tip of the probe onto a PCB track, component leg or ground plane.
A clip-on toroid attachment is also provided which converts the probe into a more conventional 'closed
magnetic loop' current probe when required.
This current probe employs a sensing method generally known as a fluxgate magnetometer, and
measures the magnetic field surrounding the electric current. The magnetometer consists of a small
coil of wire surrounding a core made of an advanced material with special magnetic properties. An
excitation current (at approximately 40MHz) is passed through the coil, which magnetises the core
alternately in opposite directions. If there is no external magnetic field, this magnetisation is
symmetrical. When an external field is applied, the resulting asymmetry is detected by a feedback
loop which applies an opposing current through the coil to restore the net field to zero. The output
voltage is proportional to this opposing current, and therefore to the magnitude of the field.
The unique feature of this probe is the very small size of the magnetometer element, which allows
fields to be measured at an accurately localised position in space, and also allows the signal
bandwidth to extend from DC up to 5MHz. Two lower bandwidth settings are also provided, which
give lower noise.
Unlike transformer based probes, which are either AC coupled only or require a separate mechanism
(such as a Hall effect device) to provide a response down to DC, this probe uses the same
measurement mechanism for all frequencies across its bandwidth.
It is intended for use with an oscilloscope with a standard 1MΩ input impedance.
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